I mean, literally no main roster character with their own style has ever disappeared for more than two main series entires in a row to date, right?
If you consider Edge Master the "mimic" style, then he was gone from SoulCalibur II-IV, so he missed three games. SoulCalibur II had Charade, and SoulCalibur III had Olcadan, so we didn't not have a mimic except for SoulCalibur IV (and now SoulCalibur VI), but if we're talking Edge Master the character,
the mimic, then he would apply, otherwise yes, it's just Li Long, unless you claimed that Maxi was the natural evolution of his style from SoulBlade. Or it could be both Hwang
and Li Long, if you don't count their appearance in SoulCalibur III as truly valid, considering they're practically treating their Arcade Edition variants like they never existed, unless Hwang proves that notion incorrect.
in general, this is how the rotation works
I disagree with this, though. SoulCalibur V is the only reason the "rotation" exists, at least for SoulCalibur. Historically, prior to SoulCalibur V (except for SoulCalibur II, where an attempt was made, before the fans said no and demanded the return of the full cast for the home release -- after that, they gave up on the idea, except what I'm about to note), everyone was kept, more or less, with a few new added per game. The only characters you could even argue have a rotation would be Hwang, and possibly Aeon and Rock. Those three are the only ones subject to any kind of will they/won't they prior to SoulCalibur V, with the three of them being nameless NPCs in SoulCalibur II, then while Aeon and Rock were restored for SoulCalibur III, Hwang was made into a bonus character (with surprise Li Long!), and then didn't return after that, regardless of being fleshed out and differentiated from Yun-seong (Maxi) more than sufficiently in Arcade Edition, it was never even considered to bring him (them) into SoulCalibur IV, as we just learned today.
Edit: Fleshed out my last sentence a bit, for clarity.